AMD Carrizo / Stoneyridge use a DesignWare 8250 UART that uses a 48 MHz
input clock.
Allow these platforms to set up this clock by specifying a kernel command
line like:
earlycon=amdcz,mmio32,0xfedc6000,115200
Signed-off-by: Daniel Kurtz <djkurtz@xxxxxxxxxxxx>
Suggested-by: Andy Shevchenko <andy.shevchenko@xxxxxxxxx>
Reviewed-by: Andy Shevchenko <andy.shevchenko@xxxxxxxxx>
---
drivers/tty/serial/8250/8250_early.c | 15 +++++++++++++++
1 file changed, 15 insertions(+)
diff --git a/drivers/tty/serial/8250/8250_early.c b/drivers/tty/serial/8250/8250_early.c
index ae6a256524d8..c6bf971a6038 100644
--- a/drivers/tty/serial/8250/8250_early.c
+++ b/drivers/tty/serial/8250/8250_early.c
@@ -195,3 +195,18 @@ static int __init early_au_setup(struct earlycon_device *dev, const char *opt)
OF_EARLYCON_DECLARE(palmchip, "ralink,rt2880-uart", early_au_setup);
#endif
+
+#ifdef CONFIG_SERIAL_8250_DW
+static int __init early_amdcz_setup(struct earlycon_device *dev,
+ const char *opt)
+{
+ struct uart_port *port = &dev->port;
+
+ port->uartclk = 48000000;
+
+ return early_serial8250_setup(dev, opt);
+}
+
+EARLYCON_DECLARE(amdcz, early_amdcz_setup);
+
+#endif
--
2.16.2.804.g6dcf76e118-goog
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